1. Technical Field
The present invention is related to a polishing pad used in a semiconductor polishing process, and more particularly is related to a polishing pad utilizing a pressure sensitive adhesive to couple.
2. Description of Related Art
Microelectronic chips are made by depositing different thin film materials on a semiconducting wafer. When a thin film material is deposited onto a wafer surface, a polishing process is employed to evenly remove the protruded portion of the deposit layer so as to planarize the wafer topography for subsequent IC manufacturing processes to proceed. This polishing procedure is so-called Chemical Mechanical Polishing (CMP). The chips are made by repeating deposition of thin-film materials, and thus many CMP steps are generally required.
In the conventional CMP process, the polishing pad is fixed on a bottom layer or a plurality of polishing pads are coupled together to form a compound polishing pad. When the polishing pad is fixed on the polishing device, a glue or adhesive liquid is used to couple the polishing pad and the polishing device. When polishing, a wafer is rotating against the polishing pad surface. The shear force generated by the polishing action will cause delamination of the polishing pad. Therefore, the polishing step is necessary to stop and the wafer may be damaged.
According to the problem described above, a polishing pad used for polishing process is disclosed in the present invention. A pressure sensitive adhesive is used to couple the polishing pad or is used to couple the polishing pad with the polishing device. The pressure sensitive adhesive has a sufficient and higher horizontal adhesion than the vertical adhesion. The polishing pad will not be delaminated by the shearing force generated by polishing action. Further the vertical adhesion of the pressure sensitive from the pad is just sufficient to couple the polishing device, and thus the polishing pad can be easily released from the polishing device.